<?php
//咖啡抽象类
abstract class Coffee {
    protected $description;
    protected $size;
    const Big = 3; //大杯
    const Mid = 2; //中杯
    const Sml = 1; //小杯
    //获取描述
    public function getDescription(){
        return $this->description;
    }
    public function getSize()
    {
        return $this->size;
    }
    public function setSize($size)
    {
        $this->size = $size;
    }
    abstract public function cost();
}